def guess(number):
    i=0
    original_number = number
    while number !=1:
        if number % 2==0:
            number =number /2
        else:
            number =number *3 + 1
        i +=1
    print(f"{original_number}经过{i}次变换后回到1")
num = int(input("请输入一个大于1的正整数："))
guess(num)